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resources:tools-software:android-drivers:sensor-acceleration:adxl345 [08 Nov 2011 16:42] – [Platform data configuration] fix dead link Lars-Peter Clausenresources:tools-software:android-drivers:sensor-acceleration:adxl345 [11 Dec 2013 09:57] (current) – [Platform data configuration] Michael Hennerich
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 +====== ADXL345/6 Android Acceleration Sensor ======
  
 +Using the ADXL345/6 under Android as Acceleration Sensor
 +
 +{{:software:driver:android:adxl_sensor_list.png|}}
 +
 +The ADXL345/6 can be easily used as Android Acceleration Sensor.
 +A few steps are necessary to add appropriate sensor support.
 +
 +===== Add Linux Driver Support: =====
 +
 +Starting with linux-2.6.36 the ADXL34x driver is mainlined.
 +If you are using an pre linux-2.6.36 kernel get the source from our repositories and add them to your kernel tree.
 +
 +Example platform data:
 +
 +<code c>
 +#include <linux/input/adxl34x.h>
 +static const struct adxl34x_platform_data adxl34x_info = {
 + .x_axis_offset = 0,
 + .y_axis_offset = 0,
 + .z_axis_offset = 0,
 + .tap_threshold = 0x31,
 + .tap_duration = 0x10,
 + .tap_latency = 0x60,
 + .tap_window = 0xF0,
 + .tap_axis_control = 0,
 + .act_axis_control = 0xFF,
 + .activity_threshold = 5,
 + .inactivity_threshold = 3,
 + .inactivity_time = 4,
 + .free_fall_threshold = 0x7,
 + .free_fall_time = 0x20,
 + .data_rate = 0x8,
 + .data_range = ADXL_FULL_RES,
 +
 + .ev_type = EV_ABS,
 + .ev_code_x = ABS_X, /* EV_REL */
 + .ev_code_y = ABS_Y, /* EV_REL */
 + .ev_code_z = ABS_Z, /* EV_REL */
 +
 + .ev_code_tap = {BTN_0, BTN_1, BTN_2}, /* EV_KEY x,y,z */
 +
 +/* .ev_code_ff = KEY_F,*/ /* EV_KEY */
 +/* .ev_code_act_inactivity = KEY_A,*/ /* EV_KEY */
 + .power_mode = ADXL_AUTO_SLEEP | ADXL_LINK,
 + .fifo_mode = ADXL_FIFO_STREAM,
 + .orientation_enable = 0, /* Disable Orientation Reports */
 + .deadzone_angle = ADXL_DEADZONE_ANGLE_10p8,
 + .divisor_length =  ADXL_LP_FILTER_DIVISOR_16,
 + /* EV_KEY {+Z, +Y, +X, -X, -Y, -Z} */
 + .ev_codes_orient_3d = {BTN_Z, BTN_Y, BTN_X, BTN_A, BTN_B, BTN_C},
 +};
 +</code>
 +
 +===== Create an Android sensor library =====
 +
 +The readme file in libhardware states: 
 +The source code for the "board" variant, usually lives under partners/...
 +The source code for "default" and "arch" would usually live under hardware/modules/.
 +
 +The sensor file is typically source code for the "board" variant.
 +However for simplicity this example puts it into a common folder structure under libhardware/modules/.
 +
 +  * Create an sensors folder under libhardware/modules
 +
 +  * Copy files sensors_adxl34x.c and Android.mk to libhardware/modules/sensors
 +
 +
 +----
 +**The files can be downloaded here:**\\
 +
 +{{:resources:tools-software:android-drivers:sensor-acceleration:android_hardware.zip|}}
 +
 +----
 +
 +
 +  * Make sure the makefile in the higher folder hierarchy picks up the one in libhardware/modules/sensors.
 +
 +  * Add following lines to: libhardware/Android.mk
 +
 +<code>
 +include $(addsuffix /Android.mk, $(addprefix $(LOCAL_PATH)/, \
 + modules/sensors \
 + ))
 +</code>
 +
 +In your platforms init.rc file make sure all ADXL34x drivers sysfs files {disable, rate} are owned by system:system
 +
 +  * Add following lines to your init.rc script:
 +
 +<code>
 +    chown system system /sys/class/input/event0/device/device/disable
 +    chown system system /sys/class/input/event0/device/device/rate
 +</code>
 +
 +<WRAP tip>
 +In case the ADXL345/6 is not always event0 you can alternatively approach via /sys/bus/i2c/devices/...
 +</WRAP>
 +
 +  * Rebuilt your Android tree
 +
 +<WRAP tip>
 +Upon start the Android log file (use logcat) should include following lines:
 +
 +<xterm>
 +I/SystemServer( 1862): Sensor Service
 +[--snip--]
 +D/SensorManager( 2064): found sensor: Analog Devices ADXL345/6 3-axis Accelerometer, handle=0
 +</xterm>
 +</WRAP>
 +
 +
 +===== Hints =====
 +
 +==== Sample Rate ====
 +
 +The ADXL345/6 sample rate is configurable.
 +The maximum sample rate is by default limited to 200Hz, to change this limit modify define ADXL_MAX_SAMPLE_RATE_VAL in the sensor file.
 +
 +<WRAP alert>
 +Very high sample rates > 400Hz can freeze your system!
 +</WRAP>
 +
 +<code c>
 +static int control_set_delay(struct sensors_control_context_t *dev, int32_t ms)
 +{
 + int rate_val;
 + int32_t us = ms * MSEC_TO_USEC;
 +
 + /*
 + * The ADXL34x Supports 16 sample rates ranging from 3200Hz-0.098Hz
 + * Calculate best fit and limit to max 200Hz (rate_val 11)
 + */
 +
 + for (rate_val = 0; rate_val < 16; rate_val++)
 + if (us  >= ((10000 * MSEC_TO_USEC) >> rate_val))
 + break;
 +
 + if (rate_val > ADXL_MAX_SAMPLE_RATE_VAL) {
 + rate_val = ADXL_MAX_SAMPLE_RATE_VAL;
 + LOGD("Control set delay %d ms requetsed, limiting to rate %d [%d mHz]\n",
 +      ms, rate_val, (3200000 >> (15 - rate_val)));
 + } else {
 + LOGD("Control set delay %d ms requetsed, using rate %d [%d mHz]\n",
 +      ms, rate_val, (3200000 >> (15 - rate_val)));
 + }
 + return write_int("rate", rate_val);
 +}
 +</code>
 +
 +==== Platform data configuration ====
 +
 +=== Don't use BTN_TOUCH ===
 +
 +In case you experience strange input device gui interaction it might be the case that Android EventHub included the ADXL34x as input device.
 +This is typically the case if you put an BTN_TOUCH key into your ADXL34x drivers platform data.
 +
 +Upon start EventHub must emit classes=0x0:
 +
 +<code>
 +I/EventHub( 1862): New device: path=/dev/input/event0 name=ADXL34x 
 +accelerometer id=0x10003 (of 0x4) index=4 fd=50 classes=0x0
 +</code>
 +classes=0x4 means that the ADXL34x driver is considered as Touchscreen.
 +
 +=== Auto Sleep ===
 +
 +The default platform configuration sets the driver automatically switch to sleep mode during periods of inactivity.
 +To disable this feature remove ADXL_AUTO_SLEEP from power_mode.
 +
 +Alternatively during runtime:
 +<code>
 +#echo 0 > /sys/class/input/event0/device/device/autosleep
 +
 +</code> 
 +
 +For more information visit the [[resources/tools-software/linux-drivers/input-misc/adxl345|ADXL34x driver page]]
 +
 +
 +==== The Sources ====
 +
 +=== Android.mk ===
 +<code c>
 +# Copyright (C) 2008 The Android Open Source Project
 +#
 +# Licensed under the Apache License, Version 2.0 (the "License");
 +# you may not use this file except in compliance with the License.
 +# You may obtain a copy of the License at
 +#
 +#      http://www.apache.org/licenses/LICENSE-2.0
 +#
 +# Unless required by applicable law or agreed to in writing, software
 +# distributed under the License is distributed on an "AS IS" BASIS,
 +# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 +# See the License for the specific language governing permissions and
 +# limitations under the License.
 +
 +
 +LOCAL_PATH := $(call my-dir)
 +
 +include $(CLEAR_VARS)
 +LOCAL_PRELINK_MODULE := false
 +LOCAL_MODULE_PATH := $(TARGET_OUT_SHARED_LIBRARIES)/hw
 +LOCAL_SHARED_LIBRARIES := liblog libcutils
 +LOCAL_SRC_FILES := sensors_adxl34x.c
 +LOCAL_MODULE := sensors.default
 +include $(BUILD_SHARED_LIBRARY)
 +</code>
 +
 +=== sensors_adxl34x.c ===
 +<code c>
 +/*
 + * Copyright (C) 2010 Analog Devices Inc.
 + * Copyright (C) 2008 The Android Open Source Project
 + *
 + * Licensed under the Apache License, Version 2.0 (the "License");
 + * you may not use this file except in compliance with the License.
 + * You may obtain a copy of the License at
 + *
 + *      http://www.apache.org/licenses/LICENSE-2.0
 + *
 + * Unless required by applicable law or agreed to in writing, software
 + * distributed under the License is distributed on an "AS IS" BASIS,
 + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 + * See the License for the specific language governing permissions and
 + * limitations under the License.
 + */
 +
 +#define LOG_TAG "sensors"
 +#define SENSORS_SERVICE_NAME "sensors"
 +#define ACCEL_SENSOR_NAME "ADXL34x accelerometer"
 +
 +#include <stdint.h>
 +#include <string.h>
 +#include <unistd.h>
 +#include <errno.h>
 +#include <fcntl.h>
 +#include <stdlib.h>
 +#include <stdio.h>
 +#include <pthread.h>
 +#include <dirent.h>
 +#include <sys/poll.h>
 +#include <sys/ioctl.h>
 +#include <sys/types.h>
 +#include <linux/input.h>
 +
 +#include <cutils/sockets.h>
 +#include <cutils/properties.h>
 +#include <cutils/atomic.h>
 +#include <cutils/log.h>
 +#include <cutils/native_handle.h>
 +
 +#include <hardware/sensors.h>
 +
 +/******************************************************************************/
 +#define ID_BASE SENSORS_HANDLE_BASE
 +#define ID_ACCELERATION (ID_BASE + 0)
 +#define MAX_NUM_SENSORS 1
 +/*
 + * This driver assumes the ADXL345/6 set in 13-bit full resolution mode +/-16g.
 + */
 +
 +#define LSG                     (256.0f) /* 3.9 mg resolution */
 +#define CONVERT                 (GRAVITY_EARTH / LSG)
 +#define CONVERT_X               CONVERT
 +#define CONVERT_Y               CONVERT
 +#define CONVERT_Z               CONVERT
 +
 +#define SENSORS_ACCELERATION    (1 << ID_ACCELERATION)
 +#define ID_A  (0)
 +#define INPUT_DIR               "/dev/input"
 +#define SUPPORTED_SENSORS       (SENSORS_ACCELERATION)
 +#define EVENT_MASK_ACCEL_ALL    ((1 << ABS_X) | (1 << ABS_Y) | (1 << ABS_Z))
 +#define DEFAULT_THRESHOLD 100
 +
 +#define ACCELERATION_X (1 << ABS_X)
 +#define ACCELERATION_Y (1 << ABS_Y)
 +#define ACCELERATION_Z (1 << ABS_Z)
 +#define SENSORS_ACCELERATION_ALL (ACCELERATION_X | ACCELERATION_Y | \
 +        ACCELERATION_Z)
 +#define SEC_TO_NSEC 1000000000LL
 +#define USEC_TO_NSEC 1000
 +#define MSEC_TO_USEC 1000
 +
 +#define ADXL_MAX_SAMPLE_RATE_VAL 11 /* 200 Hz */
 +
 +struct sensors_control_context_t {
 + struct sensors_control_device_t device;
 + int sensor_fd;
 + uint32_t active_sensors;
 +};
 +
 +struct sensors_data_context_t {
 + struct sensors_data_device_t device;
 + int event_fd;
 + sensors_data_t sensors[MAX_NUM_SENSORS];
 +};
 +
 +static char input_name[20];
 +static char devname[PATH_MAX];
 +
 +static int open_sensors_phy(struct sensors_control_device_t *dev, int keep_open)
 +{
 + char *filename;
 + int fd;
 + int res;
 + uint8_t bits[4];
 + DIR *dir;
 + struct dirent *de;
 + char name[80];
 +
 + dir = opendir(INPUT_DIR);
 + if (dir == NULL)
 + return -1;
 +
 + strcpy(devname, INPUT_DIR);
 + filename = devname + strlen(devname);
 + *filename++ = '/';
 +
 + while ((de = readdir(dir))) {
 + if (de->d_name[0] == '.' &&
 +     (de->d_name[1] == '\0' ||
 +      (de->d_name[1] == '.' && de->d_name[2] == '\0')))
 + continue;
 + strcpy(filename, de->d_name);
 + fd = open(devname, O_RDONLY);
 + if (fd < 0) {
 + LOGE("Couldn't open %s, error = %d", devname, fd);
 + continue;
 + }
 + res = ioctl(fd, EVIOCGBIT(EV_ABS, 4), bits);
 + if (res <= 0 || bits[0] != EVENT_MASK_ACCEL_ALL) {
 + close(fd);
 + continue;
 + }
 +
 + if (ioctl(fd, EVIOCGNAME(sizeof(name) - 1), &name) < 1) {
 + name[0] = '\0';
 + }
 +
 + if (!strcmp(name, ACCEL_SENSOR_NAME)) {
 + strcpy(input_name, &devname[5]);
 + LOGD("using %s (name=%s)", devname, name);
 + } else {
 + close(fd);
 + continue;
 + }
 + closedir(dir);
 + if (keep_open) {
 + return fd;
 + } else {
 + close(fd);
 + return 0;
 + }
 + }
 + closedir(dir);
 +
 + return -1;
 +}
 +
 +static int write_int(char const *item, int value)
 +{
 + int fd;
 + static int already_warned = 0;
 + char path[80];
 +
 + if (input_name[0] == 0)
 + open_sensors_phy(NULL, 0);
 +
 + sprintf(path, "/sys/class/%s/device/device/%s", input_name, item);
 +
 + fd = open(path, O_RDWR);
 + if (fd >= 0) {
 + char buffer[20];
 + int bytes = sprintf(buffer, "%d\n", value);
 + int amt = write(fd, buffer, bytes);
 + close(fd);
 + return amt == -1 ? -errno : 0;
 + } else {
 + if (already_warned == 0) {
 + LOGE("write_int failed to open %s\n", path);
 + already_warned = 1;
 + }
 + return -errno;
 + }
 +}
 +
 +/*
 + * the following is the list of all supported sensors
 + */
 +static const struct sensor_t device_sensor_list[] = {
 + {
 + .name = "Analog Devices ADXL345/6 3-axis Accelerometer",
 + .vendor = "ADI",
 + .version = 1,
 + .handle = ID_ACCELERATION,
 + .type = SENSOR_TYPE_ACCELEROMETER,
 + .maxRange = (GRAVITY_EARTH * 16.0f),
 + .resolution = (GRAVITY_EARTH * 16.0f) / 4096.0f,
 + .power = 0.145f,
 + .reserved = {},
 + },
 +};
 +
 +static int sensors_get_list(struct sensors_module_t *module,
 + struct sensor_t const **list)
 +{
 + *list = device_sensor_list;
 + return sizeof(device_sensor_list) / sizeof(device_sensor_list[0]);
 +}
 +
 +/** Close the sensors device */
 +static int sensors__common_close(struct hw_device_t *dev)
 +{
 + struct sensors_data_context_t *device_data =
 +     (struct sensors_data_context_t *)dev;
 +
 + if (device_data) {
 + if (device_data->event_fd > 0)
 + close(device_data->event_fd);
 +
 + free(device_data);
 + }
 + return 0;
 +}
 +
 +static native_handle_t* control_open_data_source(struct sensors_control_device_t *dev)
 +{
 + native_handle_t* handle;
 + int fd = open_sensors_phy(dev, 1);
 + if (fd < 0) {
 + return NULL;
 + }
 +
 + handle = native_handle_create(1, 0);
 + handle->data[0] = fd;
 +
 + return handle;
 +}
 +
 +static int control_activate(struct sensors_control_context_t *dev,
 +     int handle, int enabled)
 +{
 + uint32_t mask = (1 << handle);
 + uint32_t sensors;
 + uint32_t new_sensors, active, changed;
 + int value;
 +
 + sensors = enabled ? mask : 0;
 + active = dev->active_sensors;
 + new_sensors = (active & ~mask) | (sensors & mask);
 + changed = active ^ new_sensors;
 + if (!changed)
 + return 0;
 +
 + dev->active_sensors = new_sensors;
 +
 + if (enabled) {
 + LOGD("Activate sensor\n");
 + value = 0;
 + } else {
 + LOGD("Deactivate sensor\n");
 + value = 1;
 + }
 +
 + return write_int("disable", value);
 +}
 +
 +static int control_set_delay(struct sensors_control_context_t *dev, int32_t ms)
 +{
 + int rate_val;
 + int32_t us = ms * MSEC_TO_USEC;
 +
 + /*
 + * The ADXL34x Supports 16 sample rates ranging from 3200Hz-0.098Hz
 + * Calculate best fit and limit to max 200Hz (rate_val 11)
 + */
 +
 + for (rate_val = 0; rate_val < 16; rate_val++)
 + if (us  >= ((10000 * MSEC_TO_USEC) >> rate_val))
 + break;
 +
 + if (rate_val > ADXL_MAX_SAMPLE_RATE_VAL) {
 + rate_val = ADXL_MAX_SAMPLE_RATE_VAL;
 + LOGD("Control set delay %d ms requetsed, limiting to rate %d [%d mHz]\n",
 +      ms, rate_val, (3200000 >> (15 - rate_val)));
 + } else {
 + LOGD("Control set delay %d ms requetsed, using rate %d [%d mHz]\n",
 +      ms, rate_val, (3200000 >> (15 - rate_val)));
 + }
 + return write_int("rate", rate_val);
 +}
 +
 +static int control_wake(struct sensors_control_context_t *dev)
 +{
 + int err = 0;
 + int fd = open(devname, O_WRONLY);
 + if (fd > 0) {
 + struct input_event event[1];
 + event[0].type = EV_SYN;
 + event[0].code = SYN_CONFIG;
 + event[0].value = 0;
 + err = write(fd, event, sizeof(event));
 + LOGD_IF(err < 0, "control__wake, err=%d (%s)", errno, strerror(errno));
 + close(fd);
 + }
 + return err;
 +}
 +
 +static int control_close(struct hw_device_t *dev)
 +{
 + struct sensors_control_context_t *device_control = (void *)dev;
 +
 + if (device_control) {
 + if (device_control->sensor_fd > 0)
 + close(device_control->sensor_fd);
 + free(device_control);
 + }
 +
 + return 0;
 +}
 +
 +static int sensors__data_open(struct sensors_data_context_t *dev, native_handle_t* handle)
 +{
 + int i;
 + memset(&dev->sensors, 0, sizeof(dev->sensors));
 +
 + for (i = 0; i < MAX_NUM_SENSORS; i++) {
 + dev->sensors[i].vector.status = SENSOR_STATUS_ACCURACY_HIGH;
 + }
 + dev->event_fd = dup(handle->data[0]);
 + /* native_handle_close(handle); */
 + native_handle_delete(handle);
 + return 0;
 +
 +}
 +
 +static int sensors__data_close(struct sensors_data_device_t *dev)
 +{
 + struct sensors_data_context_t *data_device =
 +     (struct sensors_data_context_t *)dev;
 +
 + if (data_device->event_fd > 0) {
 + close(data_device->event_fd);
 + }
 +
 + return 0;
 +}
 +
 +static int sensors__data_poll(struct sensors_data_context_t *dev, sensors_data_t * values)
 +{
 + struct input_event ev;
 + int ret;
 + uint32_t new_sensors = 0;
 + int fd = dev->event_fd;
 +
 + while (1) {
 + ret = read(fd, &ev, sizeof(ev));
 +
 + if (ret < (int)sizeof(ev))
 + break;
 +
 + if (ev.type == EV_ABS) {
 + /* Orientation or acceleration event */
 + switch (ev.code) {
 + case ABS_X:
 + new_sensors |= ACCELERATION_X;
 + dev->sensors[ID_A].acceleration.x = ev.value * CONVERT_X;
 + break;
 + case ABS_Y:
 + new_sensors |= ACCELERATION_Y;
 + dev->sensors[ID_A].acceleration.y = ev.value * CONVERT_Y;
 + break;
 + case ABS_Z:
 + new_sensors |= ACCELERATION_Z;
 + dev->sensors[ID_A].acceleration.z = ev.value * CONVERT_Z;
 + break;
 + }
 + } else if (ev.type == EV_SYN) {
 +
 + if (ev.code == SYN_CONFIG) {
 + /* Injected event by control_wake
 + * return immediately
 + */
 + return 0x7FFFFFFF;
 + }
 +
 + /*
 + * Linux Input suppresses identical events, so if
 + * only ABS_Z changes and ABS_X,Y stays constant
 + * between events we need to report the cached values.
 + * Many other drivers start to scramble events by
 + * waiting for a full triplet to arrive.
 + * Other events on the ADXL345/6 such as TAP
 + * should be turned off.
 + */
 + if (new_sensors) {
 + int64_t t =
 +     ev.time.tv_sec * SEC_TO_NSEC +
 +     ev.time.tv_usec * USEC_TO_NSEC;
 + new_sensors = 0;
 +
 + dev->sensors[ID_A].time = t;
 + *values = dev->sensors[ID_A];
 + values->sensor = ID_ACCELERATION;
 + return ID_ACCELERATION;
 + }
 + }
 + }
 + return 0;
 +}
 +
 +/******************************************************************************/
 +
 +/**
 + * module methods
 + */
 +
 +/** Open a new instance of a sensor device using name */
 +static int open_sensors(const struct hw_module_t *module, const char *name,
 + struct hw_device_t **device)
 +{
 + int status = -EINVAL;
 + if (!strcmp(name, SENSORS_HARDWARE_CONTROL)) {
 + struct sensors_control_context_t *dev;
 + dev = malloc(sizeof(*dev));
 + memset(dev, 0, sizeof(*dev));
 + dev->sensor_fd = -1;
 + dev->device.common.tag = HARDWARE_DEVICE_TAG;
 + dev->device.common.version = 0;
 + dev->device.common.module = (struct hw_module_t *)module;
 + dev->device.common.close = control_close;
 + dev->device.open_data_source = control_open_data_source;
 + dev->device.activate = control_activate;
 + dev->device.set_delay = control_set_delay;
 + dev->device.wake = control_wake;
 + *device = &dev->device.common;
 + } else if (!strcmp(name, SENSORS_HARDWARE_DATA)) {
 + struct sensors_data_context_t *dev;
 + dev = malloc(sizeof(*dev));
 + memset(dev, 0, sizeof(*dev));
 + dev->event_fd = -1;
 + dev->device.common.tag = HARDWARE_DEVICE_TAG;
 + dev->device.common.version = 0;
 + dev->device.common.module = (struct hw_module_t *)module;
 + dev->device.common.close = sensors__common_close;
 + dev->device.data_open = sensors__data_open;
 + dev->device.data_close = sensors__data_close;
 + dev->device.poll = sensors__data_poll;
 + *device = &dev->device.common;
 + }
 + return status;
 +}
 +
 +static struct hw_module_methods_t sensors_module_methods = {
 + .open = open_sensors,
 +};
 +
 +/*
 + * The Sensors Hardware Module
 + */
 +const struct sensors_module_t HAL_MODULE_INFO_SYM = {
 + .common = {
 +    .tag = HARDWARE_MODULE_TAG,
 +    .version_major = 1,
 +    .version_minor = 0,
 +    .id = SENSORS_HARDWARE_MODULE_ID,
 +    .name = "Analog Devices ADXL345/6 sensor",
 +    .author = "OPS MH",
 +    .methods = &sensors_module_methods,
 +    },
 + .get_sensors_list = sensors_get_list,
 +};
 +
 +</code>
resources/tools-software/android-drivers/sensor-acceleration/adxl345.txt · Last modified: 11 Dec 2013 09:57 by Michael Hennerich

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